--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/mujs/regexp.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,1277 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <setjmp.h>
+#include <limits.h>
+
+#include "regexp.h"
+#include "utf.h"
+
+#define emit regemit
+#define next regnext
+#define accept regaccept
+
+#define nelem(a) (int)(sizeof (a) / sizeof (a)[0])
+
+#define REPINF 255
+#ifndef REG_MAXPROG
+#define REG_MAXPROG (32 << 10)
+#endif
+#ifndef REG_MAXREC
+#define REG_MAXREC 1024
+#endif
+#ifndef REG_MAXSPAN
+#define REG_MAXSPAN 64
+#endif
+#ifndef REG_MAXCLASS
+#define REG_MAXCLASS 128
+#endif
+
+typedef struct Reclass Reclass;
+typedef struct Renode Renode;
+typedef struct Reinst Reinst;
+typedef struct Rethread Rethread;
+
+struct Reclass {
+	Rune *end;
+	Rune spans[REG_MAXSPAN];
+};
+
+struct Reprog {
+	Reinst *start, *end;
+	Reclass *cclass;
+	int flags;
+	int nsub;
+};
+
+struct cstate {
+	Reprog *prog;
+	Renode *pstart, *pend;
+
+	const char *source;
+	int ncclass;
+	int nsub;
+	Renode *sub[REG_MAXSUB];
+
+	int lookahead;
+	Rune yychar;
+	Reclass *yycc;
+	int yymin, yymax;
+
+	const char *error;
+	jmp_buf kaboom;
+
+	Reclass cclass[REG_MAXCLASS];
+};
+
+static void die(struct cstate *g, const char *message)
+{
+	g->error = message;
+	longjmp(g->kaboom, 1);
+}
+
+static int canon(Rune c)
+{
+	Rune u = toupperrune(c);
+	if (c >= 128 && u < 128)
+		return c;
+	return u;
+}
+
+/* Scan */
+
+enum {
+	L_CHAR = 256,
+	L_CCLASS,	/* character class */
+	L_NCCLASS,	/* negative character class */
+	L_NC,		/* "(?:" no capture */
+	L_PLA,		/* "(?=" positive lookahead */
+	L_NLA,		/* "(?!" negative lookahead */
+	L_WORD,		/* "\b" word boundary */
+	L_NWORD,	/* "\B" non-word boundary */
+	L_REF,		/* "\1" back-reference */
+	L_COUNT,	/* {M,N} */
+};
+
+static int hex(struct cstate *g, int c)
+{
+	if (c >= '0' && c <= '9') return c - '0';
+	if (c >= 'a' && c <= 'f') return c - 'a' + 0xA;
+	if (c >= 'A' && c <= 'F') return c - 'A' + 0xA;
+	die(g, "invalid escape sequence");
+	return 0;
+}
+
+static int dec(struct cstate *g, int c)
+{
+	if (c >= '0' && c <= '9') return c - '0';
+	die(g, "invalid quantifier");
+	return 0;
+}
+
+#define ESCAPES "BbDdSsWw^$\\.*+?()[]{}|-0123456789"
+
+static int isunicodeletter(int c)
+{
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || isalpharune(c);
+}
+
+static int nextrune(struct cstate *g)
+{
+	if (!*g->source) {
+		g->yychar = EOF;
+		return 0;
+	}
+	g->source += chartorune(&g->yychar, g->source);
+	if (g->yychar == '\\') {
+		if (!*g->source)
+			die(g, "unterminated escape sequence");
+		g->source += chartorune(&g->yychar, g->source);
+		switch (g->yychar) {
+		case 'f': g->yychar = '\f'; return 0;
+		case 'n': g->yychar = '\n'; return 0;
+		case 'r': g->yychar = '\r'; return 0;
+		case 't': g->yychar = '\t'; return 0;
+		case 'v': g->yychar = '\v'; return 0;
+		case 'c':
+			if (!g->source[0])
+				die(g, "unterminated escape sequence");
+			g->yychar = (*g->source++) & 31;
+			return 0;
+		case 'x':
+			if (!g->source[0] || !g->source[1])
+				die(g, "unterminated escape sequence");
+			g->yychar = hex(g, *g->source++) << 4;
+			g->yychar += hex(g, *g->source++);
+			if (g->yychar == 0) {
+				g->yychar = '0';
+				return 1;
+			}
+			return 0;
+		case 'u':
+			if (!g->source[0] || !g->source[1] || !g->source[2] || !g->source[3])
+				die(g, "unterminated escape sequence");
+			g->yychar = hex(g, *g->source++) << 12;
+			g->yychar += hex(g, *g->source++) << 8;
+			g->yychar += hex(g, *g->source++) << 4;
+			g->yychar += hex(g, *g->source++);
+			if (g->yychar == 0) {
+				g->yychar = '0';
+				return 1;
+			}
+			return 0;
+		case 0:
+			g->yychar = '0';
+			return 1;
+		}
+		if (strchr(ESCAPES, g->yychar))
+			return 1;
+		if (isunicodeletter(g->yychar) || g->yychar == '_') /* check identity escape */
+			die(g, "invalid escape character");
+		return 0;
+	}
+	return 0;
+}
+
+static int lexcount(struct cstate *g)
+{
+	g->yychar = *g->source++;
+
+	g->yymin = dec(g, g->yychar);
+	g->yychar = *g->source++;
+	while (g->yychar != ',' && g->yychar != '}') {
+		g->yymin = g->yymin * 10 + dec(g, g->yychar);
+		g->yychar = *g->source++;
+		if (g->yymin >= REPINF)
+			die(g, "numeric overflow");
+	}
+
+	if (g->yychar == ',') {
+		g->yychar = *g->source++;
+		if (g->yychar == '}') {
+			g->yymax = REPINF;
+		} else {
+			g->yymax = dec(g, g->yychar);
+			g->yychar = *g->source++;
+			while (g->yychar != '}') {
+				g->yymax = g->yymax * 10 + dec(g, g->yychar);
+				g->yychar = *g->source++;
+				if (g->yymax >= REPINF)
+					die(g, "numeric overflow");
+			}
+		}
+	} else {
+		g->yymax = g->yymin;
+	}
+
+	return L_COUNT;
+}
+
+static void newcclass(struct cstate *g)
+{
+	if (g->ncclass >= REG_MAXCLASS)
+		die(g, "too many character classes");
+	g->yycc = g->cclass + g->ncclass++;
+	g->yycc->end = g->yycc->spans;
+}
+
+static void addrange(struct cstate *g, Rune a, Rune b)
+{
+	Reclass *cc = g->yycc;
+	Rune *p;
+
+	if (a > b)
+		die(g, "invalid character class range");
+
+	/* extend existing ranges if they overlap */
+	for (p = cc->spans; p < cc->end; p += 2) {
+		/* completely inside old range */
+		if (a >= p[0] && b <= p[1])
+			return;
+
+		/* completely swallows old range */
+		if (a < p[0] && b >= p[1]) {
+			p[0] = a;
+			p[1] = b;
+			return;
+		}
+
+		/* extend at start */
+		if (b >= p[0] - 1 && b <= p[1] && a < p[0]) {
+			p[0] = a;
+			return;
+		}
+
+		/* extend at end */
+		if (a >= p[0] && a <= p[1] + 1 && b > p[1]) {
+			p[1] = b;
+			return;
+		}
+	}
+
+	if (cc->end + 2 >= cc->spans + nelem(cc->spans))
+		die(g, "too many character class ranges");
+	*cc->end++ = a;
+	*cc->end++ = b;
+}
+
+static void addranges_d(struct cstate *g)
+{
+	addrange(g, '0', '9');
+}
+
+static void addranges_D(struct cstate *g)
+{
+	addrange(g, 0, '0'-1);
+	addrange(g, '9'+1, 0xFFFF);
+}
+
+static void addranges_s(struct cstate *g)
+{
+	addrange(g, 0x9, 0xD);
+	addrange(g, 0x20, 0x20);
+	addrange(g, 0xA0, 0xA0);
+	addrange(g, 0x2028, 0x2029);
+	addrange(g, 0xFEFF, 0xFEFF);
+}
+
+static void addranges_S(struct cstate *g)
+{
+	addrange(g, 0, 0x9-1);
+	addrange(g, 0xD+1, 0x20-1);
+	addrange(g, 0x20+1, 0xA0-1);
+	addrange(g, 0xA0+1, 0x2028-1);
+	addrange(g, 0x2029+1, 0xFEFF-1);
+	addrange(g, 0xFEFF+1, 0xFFFF);
+}
+
+static void addranges_w(struct cstate *g)
+{
+	addrange(g, '0', '9');
+	addrange(g, 'A', 'Z');
+	addrange(g, '_', '_');
+	addrange(g, 'a', 'z');
+}
+
+static void addranges_W(struct cstate *g)
+{
+	addrange(g, 0, '0'-1);
+	addrange(g, '9'+1, 'A'-1);
+	addrange(g, 'Z'+1, '_'-1);
+	addrange(g, '_'+1, 'a'-1);
+	addrange(g, 'z'+1, 0xFFFF);
+}
+
+static int lexclass(struct cstate *g)
+{
+	int type = L_CCLASS;
+	int quoted, havesave, havedash;
+	Rune save = 0;
+
+	newcclass(g);
+
+	quoted = nextrune(g);
+	if (!quoted && g->yychar == '^') {
+		type = L_NCCLASS;
+		quoted = nextrune(g);
+	}
+
+	havesave = havedash = 0;
+	for (;;) {
+		if (g->yychar == EOF)
+			die(g, "unterminated character class");
+		if (!quoted && g->yychar == ']')
+			break;
+
+		if (!quoted && g->yychar == '-') {
+			if (havesave) {
+				if (havedash) {
+					addrange(g, save, '-');
+					havesave = havedash = 0;
+				} else {
+					havedash = 1;
+				}
+			} else {
+				save = '-';
+				havesave = 1;
+			}
+		} else if (quoted && strchr("DSWdsw", g->yychar)) {
+			if (havesave) {
+				addrange(g, save, save);
+				if (havedash)
+					addrange(g, '-', '-');
+			}
+			switch (g->yychar) {
+			case 'd': addranges_d(g); break;
+			case 's': addranges_s(g); break;
+			case 'w': addranges_w(g); break;
+			case 'D': addranges_D(g); break;
+			case 'S': addranges_S(g); break;
+			case 'W': addranges_W(g); break;
+			}
+			havesave = havedash = 0;
+		} else {
+			if (quoted) {
+				if (g->yychar == 'b')
+					g->yychar = '\b';
+				else if (g->yychar == '0')
+					g->yychar = 0;
+				/* else identity escape */
+			}
+			if (havesave) {
+				if (havedash) {
+					addrange(g, save, g->yychar);
+					havesave = havedash = 0;
+				} else {
+					addrange(g, save, save);
+					save = g->yychar;
+				}
+			} else {
+				save = g->yychar;
+				havesave = 1;
+			}
+		}
+
+		quoted = nextrune(g);
+	}
+
+	if (havesave) {
+		addrange(g, save, save);
+		if (havedash)
+			addrange(g, '-', '-');
+	}
+
+	return type;
+}
+
+static int lex(struct cstate *g)
+{
+	int quoted = nextrune(g);
+	if (quoted) {
+		switch (g->yychar) {
+		case 'b': return L_WORD;
+		case 'B': return L_NWORD;
+		case 'd': newcclass(g); addranges_d(g); return L_CCLASS;
+		case 's': newcclass(g); addranges_s(g); return L_CCLASS;
+		case 'w': newcclass(g); addranges_w(g); return L_CCLASS;
+		case 'D': newcclass(g); addranges_d(g); return L_NCCLASS;
+		case 'S': newcclass(g); addranges_s(g); return L_NCCLASS;
+		case 'W': newcclass(g); addranges_w(g); return L_NCCLASS;
+		case '0': g->yychar = 0; return L_CHAR;
+		}
+		if (g->yychar >= '0' && g->yychar <= '9') {
+			g->yychar -= '0';
+			if (*g->source >= '0' && *g->source <= '9')
+				g->yychar = g->yychar * 10 + *g->source++ - '0';
+			return L_REF;
+		}
+		return L_CHAR;
+	}
+
+	switch (g->yychar) {
+	case EOF:
+	case '$': case ')': case '*': case '+':
+	case '.': case '?': case '^': case '|':
+		return g->yychar;
+	}
+
+	if (g->yychar == '{')
+		return lexcount(g);
+	if (g->yychar == '[')
+		return lexclass(g);
+	if (g->yychar == '(') {
+		if (g->source[0] == '?') {
+			if (g->source[1] == ':') {
+				g->source += 2;
+				return L_NC;
+			}
+			if (g->source[1] == '=') {
+				g->source += 2;
+				return L_PLA;
+			}
+			if (g->source[1] == '!') {
+				g->source += 2;
+				return L_NLA;
+			}
+		}
+		return '(';
+	}
+
+	return L_CHAR;
+}
+
+/* Parse */
+
+enum {
+	P_CAT, P_ALT, P_REP,
+	P_BOL, P_EOL, P_WORD, P_NWORD,
+	P_PAR, P_PLA, P_NLA,
+	P_ANY, P_CHAR, P_CCLASS, P_NCCLASS,
+	P_REF,
+};
+
+struct Renode {
+	unsigned char type;
+	unsigned char ng, m, n;
+	Rune c;
+	int cc;
+	Renode *x;
+	Renode *y;
+};
+
+static Renode *newnode(struct cstate *g, int type)
+{
+	Renode *node = g->pend++;
+	node->type = type;
+	node->cc = -1;
+	node->c = 0;
+	node->ng = 0;
+	node->m = 0;
+	node->n = 0;
+	node->x = node->y = NULL;
+	return node;
+}
+
+static int empty(Renode *node)
+{
+	if (!node) return 1;
+	switch (node->type) {
+	default: return 1;
+	case P_CAT: return empty(node->x) && empty(node->y);
+	case P_ALT: return empty(node->x) || empty(node->y);
+	case P_REP: return empty(node->x) || node->m == 0;
+	case P_PAR: return empty(node->x);
+	case P_REF: return empty(node->x);
+	case P_ANY: case P_CHAR: case P_CCLASS: case P_NCCLASS: return 0;
+	}
+}
+
+static Renode *newrep(struct cstate *g, Renode *atom, int ng, int min, int max)
+{
+	Renode *rep = newnode(g, P_REP);
+	if (max == REPINF && empty(atom))
+		die(g, "infinite loop matching the empty string");
+	rep->ng = ng;
+	rep->m = min;
+	rep->n = max;
+	rep->x = atom;
+	return rep;
+}
+
+static void next(struct cstate *g)
+{
+	g->lookahead = lex(g);
+}
+
+static int accept(struct cstate *g, int t)
+{
+	if (g->lookahead == t) {
+		next(g);
+		return 1;
+	}
+	return 0;
+}
+
+static Renode *parsealt(struct cstate *g);
+
+static Renode *parseatom(struct cstate *g)
+{
+	Renode *atom;
+	if (g->lookahead == L_CHAR) {
+		atom = newnode(g, P_CHAR);
+		atom->c = g->yychar;
+		next(g);
+		return atom;
+	}
+	if (g->lookahead == L_CCLASS) {
+		atom = newnode(g, P_CCLASS);
+		atom->cc = g->yycc - g->cclass;
+		next(g);
+		return atom;
+	}
+	if (g->lookahead == L_NCCLASS) {
+		atom = newnode(g, P_NCCLASS);
+		atom->cc = g->yycc - g->cclass;
+		next(g);
+		return atom;
+	}
+	if (g->lookahead == L_REF) {
+		atom = newnode(g, P_REF);
+		if (g->yychar == 0 || g->yychar >= g->nsub || !g->sub[g->yychar])
+			die(g, "invalid back-reference");
+		atom->n = g->yychar;
+		atom->x = g->sub[g->yychar];
+		next(g);
+		return atom;
+	}
+	if (accept(g, '.'))
+		return newnode(g, P_ANY);
+	if (accept(g, '(')) {
+		atom = newnode(g, P_PAR);
+		if (g->nsub == REG_MAXSUB)
+			die(g, "too many captures");
+		atom->n = g->nsub++;
+		atom->x = parsealt(g);
+		g->sub[atom->n] = atom;
+		if (!accept(g, ')'))
+			die(g, "unmatched '('");
+		return atom;
+	}
+	if (accept(g, L_NC)) {
+		atom = parsealt(g);
+		if (!accept(g, ')'))
+			die(g, "unmatched '('");
+		return atom;
+	}
+	if (accept(g, L_PLA)) {
+		atom = newnode(g, P_PLA);
+		atom->x = parsealt(g);
+		if (!accept(g, ')'))
+			die(g, "unmatched '('");
+		return atom;
+	}
+	if (accept(g, L_NLA)) {
+		atom = newnode(g, P_NLA);
+		atom->x = parsealt(g);
+		if (!accept(g, ')'))
+			die(g, "unmatched '('");
+		return atom;
+	}
+	die(g, "syntax error");
+	return NULL;
+}
+
+static Renode *parserep(struct cstate *g)
+{
+	Renode *atom;
+
+	if (accept(g, '^')) return newnode(g, P_BOL);
+	if (accept(g, '$')) return newnode(g, P_EOL);
+	if (accept(g, L_WORD)) return newnode(g, P_WORD);
+	if (accept(g, L_NWORD)) return newnode(g, P_NWORD);
+
+	atom = parseatom(g);
+	if (g->lookahead == L_COUNT) {
+		int min = g->yymin, max = g->yymax;
+		next(g);
+		if (max < min)
+			die(g, "invalid quantifier");
+		return newrep(g, atom, accept(g, '?'), min, max);
+	}
+	if (accept(g, '*')) return newrep(g, atom, accept(g, '?'), 0, REPINF);
+	if (accept(g, '+')) return newrep(g, atom, accept(g, '?'), 1, REPINF);
+	if (accept(g, '?')) return newrep(g, atom, accept(g, '?'), 0, 1);
+	return atom;
+}
+
+static Renode *parsecat(struct cstate *g)
+{
+	Renode *cat, *head, **tail;
+	if (g->lookahead != EOF && g->lookahead != '|' && g->lookahead != ')') {
+		/* Build a right-leaning tree by splicing in new 'cat' at the tail. */
+		head = parserep(g);
+		tail = &head;
+		while (g->lookahead != EOF && g->lookahead != '|' && g->lookahead != ')') {
+			cat = newnode(g, P_CAT);
+			cat->x = *tail;
+			cat->y = parserep(g);
+			*tail = cat;
+			tail = &cat->y;
+		}
+		return head;
+	}
+	return NULL;
+}
+
+static Renode *parsealt(struct cstate *g)
+{
+	Renode *alt, *x;
+	alt = parsecat(g);
+	while (accept(g, '|')) {
+		x = alt;
+		alt = newnode(g, P_ALT);
+		alt->x = x;
+		alt->y = parsecat(g);
+	}
+	return alt;
+}
+
+/* Compile */
+
+enum {
+	I_END, I_JUMP, I_SPLIT, I_PLA, I_NLA,
+	I_ANYNL, I_ANY, I_CHAR, I_CCLASS, I_NCCLASS, I_REF,
+	I_BOL, I_EOL, I_WORD, I_NWORD,
+	I_LPAR, I_RPAR
+};
+
+struct Reinst {
+	unsigned char opcode;
+	unsigned char n;
+	Rune c;
+	Reclass *cc;
+	Reinst *x;
+	Reinst *y;
+};
+
+static int count(struct cstate *g, Renode *node, int depth)
+{
+	int min, max, n;
+	if (!node) return 0;
+	if (++depth > REG_MAXREC) die(g, "stack overflow");
+	switch (node->type) {
+	default: return 1;
+	case P_CAT: return count(g, node->x, depth) + count(g, node->y, depth);
+	case P_ALT: return count(g, node->x, depth) + count(g, node->y, depth) + 2;
+	case P_REP:
+		min = node->m;
+		max = node->n;
+		if (min == max) n = count(g, node->x, depth) * min;
+		else if (max < REPINF) n = count(g, node->x, depth) * max + (max - min);
+		else n = count(g, node->x, depth) * (min + 1) + 2;
+		if (n < 0 || n > REG_MAXPROG) die(g, "program too large");
+		return n;
+	case P_PAR: return count(g, node->x, depth) + 2;
+	case P_PLA: return count(g, node->x, depth) + 2;
+	case P_NLA: return count(g, node->x, depth) + 2;
+	}
+}
+
+static Reinst *emit(Reprog *prog, int opcode)
+{
+	Reinst *inst = prog->end++;
+	inst->opcode = opcode;
+	inst->n = 0;
+	inst->c = 0;
+	inst->cc = NULL;
+	inst->x = inst->y = NULL;
+	return inst;
+}
+
+static void compile(Reprog *prog, Renode *node)
+{
+	Reinst *inst, *split, *jump;
+	int i;
+
+loop:
+	if (!node)
+		return;
+
+	switch (node->type) {
+	case P_CAT:
+		compile(prog, node->x);
+		node = node->y;
+		goto loop;
+
+	case P_ALT:
+		split = emit(prog, I_SPLIT);
+		compile(prog, node->x);
+		jump = emit(prog, I_JUMP);
+		compile(prog, node->y);
+		split->x = split + 1;
+		split->y = jump + 1;
+		jump->x = prog->end;
+		break;
+
+	case P_REP:
+		inst = NULL; /* silence compiler warning. assert(node->m > 0). */
+		for (i = 0; i < node->m; ++i) {
+			inst = prog->end;
+			compile(prog, node->x);
+		}
+		if (node->m == node->n)
+			break;
+		if (node->n < REPINF) {
+			for (i = node->m; i < node->n; ++i) {
+				split = emit(prog, I_SPLIT);
+				compile(prog, node->x);
+				if (node->ng) {
+					split->y = split + 1;
+					split->x = prog->end;
+				} else {
+					split->x = split + 1;
+					split->y = prog->end;
+				}
+			}
+		} else if (node->m == 0) {
+			split = emit(prog, I_SPLIT);
+			compile(prog, node->x);
+			jump = emit(prog, I_JUMP);
+			if (node->ng) {
+				split->y = split + 1;
+				split->x = prog->end;
+			} else {
+				split->x = split + 1;
+				split->y = prog->end;
+			}
+			jump->x = split;
+		} else {
+			split = emit(prog, I_SPLIT);
+			if (node->ng) {
+				split->y = inst;
+				split->x = prog->end;
+			} else {
+				split->x = inst;
+				split->y = prog->end;
+			}
+		}
+		break;
+
+	case P_BOL: emit(prog, I_BOL); break;
+	case P_EOL: emit(prog, I_EOL); break;
+	case P_WORD: emit(prog, I_WORD); break;
+	case P_NWORD: emit(prog, I_NWORD); break;
+
+	case P_PAR:
+		inst = emit(prog, I_LPAR);
+		inst->n = node->n;
+		compile(prog, node->x);
+		inst = emit(prog, I_RPAR);
+		inst->n = node->n;
+		break;
+	case P_PLA:
+		split = emit(prog, I_PLA);
+		compile(prog, node->x);
+		emit(prog, I_END);
+		split->x = split + 1;
+		split->y = prog->end;
+		break;
+	case P_NLA:
+		split = emit(prog, I_NLA);
+		compile(prog, node->x);
+		emit(prog, I_END);
+		split->x = split + 1;
+		split->y = prog->end;
+		break;
+
+	case P_ANY:
+		emit(prog, I_ANY);
+		break;
+	case P_CHAR:
+		inst = emit(prog, I_CHAR);
+		inst->c = (prog->flags & REG_ICASE) ? canon(node->c) : node->c;
+		break;
+	case P_CCLASS:
+		inst = emit(prog, I_CCLASS);
+		inst->cc = prog->cclass + node->cc;
+		break;
+	case P_NCCLASS:
+		inst = emit(prog, I_NCCLASS);
+		inst->cc = prog->cclass + node->cc;
+		break;
+	case P_REF:
+		inst = emit(prog, I_REF);
+		inst->n = node->n;
+		break;
+	}
+}
+
+#ifdef TEST
+static void dumpnode(struct cstate *g, Renode *node)
+{
+	Rune *p;
+	Reclass *cc;
+	if (!node) { printf("Empty"); return; }
+	switch (node->type) {
+	case P_CAT: printf("Cat("); dumpnode(g, node->x); printf(", "); dumpnode(g, node->y); printf(")"); break;
+	case P_ALT: printf("Alt("); dumpnode(g, node->x); printf(", "); dumpnode(g, node->y); printf(")"); break;
+	case P_REP:
+		printf(node->ng ? "NgRep(%d,%d," : "Rep(%d,%d,", node->m, node->n);
+		dumpnode(g, node->x);
+		printf(")");
+		break;
+	case P_BOL: printf("Bol"); break;
+	case P_EOL: printf("Eol"); break;
+	case P_WORD: printf("Word"); break;
+	case P_NWORD: printf("NotWord"); break;
+	case P_PAR: printf("Par(%d,", node->n); dumpnode(g, node->x); printf(")"); break;
+	case P_PLA: printf("PLA("); dumpnode(g, node->x); printf(")"); break;
+	case P_NLA: printf("NLA("); dumpnode(g, node->x); printf(")"); break;
+	case P_ANY: printf("Any"); break;
+	case P_CHAR: printf("Char(%c)", node->c); break;
+	case P_CCLASS:
+		printf("Class(");
+		cc = g->cclass + node->cc;
+		for (p = cc->spans; p < cc->end; p += 2) printf("%02X-%02X,", p[0], p[1]);
+		printf(")");
+		break;
+	case P_NCCLASS:
+		printf("NotClass(");
+		cc = g->cclass + node->cc;
+		for (p = cc->spans; p < cc->end; p += 2) printf("%02X-%02X,", p[0], p[1]);
+		printf(")");
+		break;
+	case P_REF: printf("Ref(%d)", node->n); break;
+	}
+}
+
+static void dumpcclass(Reclass *cc) {
+	Rune *p;
+	for (p = cc->spans; p < cc->end; p += 2) {
+		if (p[0] > 32 && p[0] < 127)
+			printf(" %c", p[0]);
+		else
+			printf(" \\x%02x", p[0]);
+		if (p[1] > 32 && p[1] < 127)
+			printf("-%c", p[1]);
+		else
+			printf("-\\x%02x", p[1]);
+	}
+	putchar('\n');
+}
+
+static void dumpprog(Reprog *prog)
+{
+	Reinst *inst;
+	int i;
+	for (i = 0, inst = prog->start; inst < prog->end; ++i, ++inst) {
+		printf("% 5d: ", i);
+		switch (inst->opcode) {
+		case I_END: puts("end"); break;
+		case I_JUMP: printf("jump %d\n", (int)(inst->x - prog->start)); break;
+		case I_SPLIT: printf("split %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
+		case I_PLA: printf("pla %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
+		case I_NLA: printf("nla %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
+		case I_ANY: puts("any"); break;
+		case I_ANYNL: puts("anynl"); break;
+		case I_CHAR: printf(inst->c >= 32 && inst->c < 127 ? "char '%c'\n" : "char U+%04X\n", inst->c); break;
+		case I_CCLASS: printf("cclass"); dumpcclass(inst->cc); break;
+		case I_NCCLASS: printf("ncclass"); dumpcclass(inst->cc); break;
+		case I_REF: printf("ref %d\n", inst->n); break;
+		case I_BOL: puts("bol"); break;
+		case I_EOL: puts("eol"); break;
+		case I_WORD: puts("word"); break;
+		case I_NWORD: puts("nword"); break;
+		case I_LPAR: printf("lpar %d\n", inst->n); break;
+		case I_RPAR: printf("rpar %d\n", inst->n); break;
+		}
+	}
+}
+#endif
+
+Reprog *regcompx(void *(*alloc)(void *ctx, void *p, int n), void *ctx,
+	const char *pattern, int cflags, const char **errorp)
+{
+	struct cstate g;
+	Renode *node;
+	Reinst *split, *jump;
+	int i, n;
+
+	g.pstart = NULL;
+	g.prog = NULL;
+
+	if (setjmp(g.kaboom)) {
+		if (errorp) *errorp = g.error;
+		alloc(ctx, g.pstart, 0);
+		if (g.prog) {
+			alloc(ctx, g.prog->cclass, 0);
+			alloc(ctx, g.prog->start, 0);
+			alloc(ctx, g.prog, 0);
+		}
+		return NULL;
+	}
+
+	g.prog = alloc(ctx, NULL, sizeof (Reprog));
+	if (!g.prog)
+		die(&g, "cannot allocate regular expression");
+	g.prog->start = NULL;
+	g.prog->cclass = NULL;
+
+	n = strlen(pattern) * 2;
+	if (n > REG_MAXPROG)
+		die(&g, "program too large");
+	if (n > 0) {
+		g.pstart = g.pend = alloc(ctx, NULL, sizeof (Renode) * n);
+		if (!g.pstart)
+			die(&g, "cannot allocate regular expression parse list");
+	}
+
+	g.source = pattern;
+	g.ncclass = 0;
+	g.nsub = 1;
+	for (i = 0; i < REG_MAXSUB; ++i)
+		g.sub[i] = 0;
+
+	g.prog->flags = cflags;
+
+	next(&g);
+	node = parsealt(&g);
+	if (g.lookahead == ')')
+		die(&g, "unmatched ')'");
+	if (g.lookahead != EOF)
+		die(&g, "syntax error");
+
+#ifdef TEST
+	dumpnode(&g, node);
+	putchar('\n');
+#endif
+
+	n = 6 + count(&g, node, 0);
+	if (n < 0 || n > REG_MAXPROG)
+		die(&g, "program too large");
+
+	g.prog->nsub = g.nsub;
+	g.prog->start = g.prog->end = alloc(ctx, NULL, n * sizeof (Reinst));
+	if (!g.prog->start)
+		die(&g, "cannot allocate regular expression instruction list");
+
+	if (g.ncclass > 0) {
+		g.prog->cclass = alloc(ctx, NULL, g.ncclass * sizeof (Reclass));
+		if (!g.prog->cclass)
+			die(&g, "cannot allocate regular expression character class list");
+		memcpy(g.prog->cclass, g.cclass, g.ncclass * sizeof (Reclass));
+		for (i = 0; i < g.ncclass; ++i)
+			g.prog->cclass[i].end = g.prog->cclass[i].spans + (g.cclass[i].end - g.cclass[i].spans);
+	}
+
+	split = emit(g.prog, I_SPLIT);
+	split->x = split + 3;
+	split->y = split + 1;
+	emit(g.prog, I_ANYNL);
+	jump = emit(g.prog, I_JUMP);
+	jump->x = split;
+	emit(g.prog, I_LPAR);
+	compile(g.prog, node);
+	emit(g.prog, I_RPAR);
+	emit(g.prog, I_END);
+
+#ifdef TEST
+	dumpprog(g.prog);
+#endif
+
+	alloc(ctx, g.pstart, 0);
+
+	if (errorp) *errorp = NULL;
+	return g.prog;
+}
+
+void regfreex(void *(*alloc)(void *ctx, void *p, int n), void *ctx, Reprog *prog)
+{
+	if (prog) {
+		if (prog->cclass)
+			alloc(ctx, prog->cclass, 0);
+		alloc(ctx, prog->start, 0);
+		alloc(ctx, prog, 0);
+	}
+}
+
+static void *default_alloc(void *ctx, void *p, int n)
+{
+	if (n == 0) {
+		free(p);
+		return NULL;
+	}
+	return realloc(p, (size_t)n);
+}
+
+Reprog *regcomp(const char *pattern, int cflags, const char **errorp)
+{
+	return regcompx(default_alloc, NULL, pattern, cflags, errorp);
+}
+
+void regfree(Reprog *prog)
+{
+	regfreex(default_alloc, NULL, prog);
+}
+
+/* Match */
+
+static int isnewline(int c)
+{
+	return c == 0xA || c == 0xD || c == 0x2028 || c == 0x2029;
+}
+
+static int iswordchar(int c)
+{
+	return c == '_' ||
+		(c >= 'a' && c <= 'z') ||
+		(c >= 'A' && c <= 'Z') ||
+		(c >= '0' && c <= '9');
+}
+
+static int incclass(Reclass *cc, Rune c)
+{
+	Rune *p;
+	for (p = cc->spans; p < cc->end; p += 2)
+		if (p[0] <= c && c <= p[1])
+			return 1;
+	return 0;
+}
+
+static int incclasscanon(Reclass *cc, Rune c)
+{
+	Rune *p, r;
+	for (p = cc->spans; p < cc->end; p += 2)
+		for (r = p[0]; r <= p[1]; ++r)
+			if (c == canon(r))
+				return 1;
+	return 0;
+}
+
+static int strncmpcanon(const char *a, const char *b, int n)
+{
+	Rune ra, rb;
+	int c;
+	while (n--) {
+		if (!*a) return -1;
+		if (!*b) return 1;
+		a += chartorune(&ra, a);
+		b += chartorune(&rb, b);
+		c = canon(ra) - canon(rb);
+		if (c)
+			return c;
+	}
+	return 0;
+}
+
+static int match(Reinst *pc, const char *sp, const char *bol, int flags, Resub *out, int depth)
+{
+	Resub scratch;
+	int result;
+	int i;
+	Rune c;
+
+	/* stack overflow */
+	if (depth > REG_MAXREC)
+		return -1;
+
+	for (;;) {
+		switch (pc->opcode) {
+		case I_END:
+			return 0;
+		case I_JUMP:
+			pc = pc->x;
+			break;
+		case I_SPLIT:
+			scratch = *out;
+			result = match(pc->x, sp, bol, flags, &scratch, depth+1);
+			if (result == -1)
+				return -1;
+			if (result == 0) {
+				*out = scratch;
+				return 0;
+			}
+			pc = pc->y;
+			break;
+
+		case I_PLA:
+			result = match(pc->x, sp, bol, flags, out, depth+1);
+			if (result == -1)
+				return -1;
+			if (result == 1)
+				return 1;
+			pc = pc->y;
+			break;
+		case I_NLA:
+			scratch = *out;
+			result = match(pc->x, sp, bol, flags, &scratch, depth+1);
+			if (result == -1)
+				return -1;
+			if (result == 0)
+				return 1;
+			pc = pc->y;
+			break;
+
+		case I_ANYNL:
+			if (!*sp) return 1;
+			sp += chartorune(&c, sp);
+			pc = pc + 1;
+			break;
+		case I_ANY:
+			if (!*sp) return 1;
+			sp += chartorune(&c, sp);
+			if (isnewline(c))
+				return 1;
+			pc = pc + 1;
+			break;
+		case I_CHAR:
+			if (!*sp) return 1;
+			sp += chartorune(&c, sp);
+			if (flags & REG_ICASE)
+				c = canon(c);
+			if (c != pc->c)
+				return 1;
+			pc = pc + 1;
+			break;
+		case I_CCLASS:
+			if (!*sp) return 1;
+			sp += chartorune(&c, sp);
+			if (flags & REG_ICASE) {
+				if (!incclasscanon(pc->cc, canon(c)))
+					return 1;
+			} else {
+				if (!incclass(pc->cc, c))
+					return 1;
+			}
+			pc = pc + 1;
+			break;
+		case I_NCCLASS:
+			if (!*sp) return 1;
+			sp += chartorune(&c, sp);
+			if (flags & REG_ICASE) {
+				if (incclasscanon(pc->cc, canon(c)))
+					return 1;
+			} else {
+				if (incclass(pc->cc, c))
+					return 1;
+			}
+			pc = pc + 1;
+			break;
+		case I_REF:
+			i = out->sub[pc->n].ep - out->sub[pc->n].sp;
+			if (flags & REG_ICASE) {
+				if (strncmpcanon(sp, out->sub[pc->n].sp, i))
+					return 1;
+			} else {
+				if (strncmp(sp, out->sub[pc->n].sp, i))
+					return 1;
+			}
+			if (i > 0)
+				sp += i;
+			pc = pc + 1;
+			break;
+
+		case I_BOL:
+			if (sp == bol && !(flags & REG_NOTBOL)) {
+				pc = pc + 1;
+				break;
+			}
+			if (flags & REG_NEWLINE) {
+				if (sp > bol && isnewline(sp[-1])) {
+					pc = pc + 1;
+					break;
+				}
+			}
+			return 1;
+		case I_EOL:
+			if (*sp == 0) {
+				pc = pc + 1;
+				break;
+			}
+			if (flags & REG_NEWLINE) {
+				if (isnewline(*sp)) {
+					pc = pc + 1;
+					break;
+				}
+			}
+			return 1;
+		case I_WORD:
+			i = sp > bol && iswordchar(sp[-1]);
+			i ^= iswordchar(sp[0]);
+			if (!i)
+				return 1;
+			pc = pc + 1;
+			break;
+		case I_NWORD:
+			i = sp > bol && iswordchar(sp[-1]);
+			i ^= iswordchar(sp[0]);
+			if (i)
+				return 1;
+			pc = pc + 1;
+			break;
+
+		case I_LPAR:
+			out->sub[pc->n].sp = sp;
+			pc = pc + 1;
+			break;
+		case I_RPAR:
+			out->sub[pc->n].ep = sp;
+			pc = pc + 1;
+			break;
+		default:
+			return 1;
+		}
+	}
+}
+
+int regexec(Reprog *prog, const char *sp, Resub *sub, int eflags)
+{
+	Resub scratch;
+	int i;
+
+	if (!sub)
+		sub = &scratch;
+
+	sub->nsub = prog->nsub;
+	for (i = 0; i < REG_MAXSUB; ++i)
+		sub->sub[i].sp = sub->sub[i].ep = NULL;
+
+	return match(prog->start, sp, sp, prog->flags | eflags, sub, 0);
+}
+
+#ifdef TEST
+int main(int argc, char **argv)
+{
+	const char *error;
+	const char *s;
+	Reprog *p;
+	Resub m;
+	int i;
+
+	if (argc > 1) {
+		p = regcomp(argv[1], 0, &error);
+		if (!p) {
+			fprintf(stderr, "regcomp: %s\n", error);
+			return 1;
+		}
+
+		if (argc > 2) {
+			s = argv[2];
+			printf("nsub = %d\n", p->nsub);
+			if (!regexec(p, s, &m, 0)) {
+				for (i = 0; i < m.nsub; ++i) {
+					int n = m.sub[i].ep - m.sub[i].sp;
+					if (n > 0)
+						printf("match %d: s=%d e=%d n=%d '%.*s'\n", i, (int)(m.sub[i].sp - s), (int)(m.sub[i].ep - s), n, n, m.sub[i].sp);
+					else
+						printf("match %d: n=0 ''\n", i);
+				}
+			} else {
+				printf("no match\n");
+			}
+		}
+	}
+
+	return 0;
+}
+#endif